1. Field of the Invention
The present invention relates to a wireless instrumentation system that is particularly suited for acquiring measurement data from a number of remote station sensors and transmitting the data to a central station. In the preferred embodiment, the system is designed to operate with low power transceivers and other elements and includes an automatic data relaying scheme for accommodating communications with out-of-range transceivers. In addition, a power management scheme is employed for minimizing power consumption by the remote stations.
2. Description of the Background Art
A number of measurement devices and systems are currently in use around the launch pad and within the Vehicle Assembly Building (VAB) at the Kennedy Space Center (KSC) to monitor various operational parameters of the Space Shuttle and related systems. Most of these systems use cabling to support power and data transmission. In such systems, interaction at the sensor level is not a desirable option because of extensive cabling requirements. Centralized data acquisition systems have therefore been employed, which, unless provided with redundancy, have often been the source of single point failures.
These issues have led to the need for data acquisition system that can operate in close proximity to the Orbiter, External Tank and Solid Rocket Boosters, for example, without interfering with existing electronic systems. To eliminate cabling issues, the system would have to be a wireless radio frequency (RF) system that could be interfaced with various measurement devices and would include a plurality of remote sensor stations in communication with a central station. However, limitations on both power and physical size of the remote stations would be necessary to minimize radio interference with other electronic systems and space requirements. As a result, the remote stations would have to be implemented with low power transceivers that are powered by small exhaustible power sources, e.g. batteries. Very low RF power systems can be operated in close proximity to other systems virtually interference-free. However, low RF power inherently limits the operating range of the transceivers, thus making it difficult or impossible to insure reliable communications between each remote station and the central station. Furthermore, small batteries inherently imply short life which means that a power management scheme would be necessary to maximize energy utilization and battery life of each remote station.